Tier 4 application.Need help,"mistakes while submitting document"

I made a mistake while submitting tier 4 application.The question was asked "Are you now or have you ever been known by another name?”. Which by mistake I answered No.In my old passport my name was written different whereas i put all my details in old passport section.i was so young when my first passport was made.at that time my name was different.When i complete my matriculation.i changed my name.So,currently in all my documents my name is same now including current passport.and also i write course end date 2018 instead of 2019.Is it ok to add affidavit while submitting documents?Need help.What should i do now?